Mechanism for controlling devices on sewing machines



K. WINZ June 17, 1958 MECHANISM FOR CONTROLLING DEVICES ON SEWING MACHINES Filed Aug. 13. 1954 lnite States Patent MECHANISM FOR CONTROLLING DEVICES ON SEWING MACHINES Karl Winz, Kaisersiautern, Germany, assignor to G. M.

Pfaff A.-G., Kaiserslautern, Pfalz, Germany, a corporation of Germany Application August 13, 1954, Serial No. 449,580 Claims priority, application Germany August 17, 1953 1 Claim. (Cl. 200-52) The present invention relates to the control of devices on sewing machines and has for its primary object the provision of means for opening and closing electric circuits, by or through which the operations of the sewing machine devices are influenced. Thus the invention is particularly concerned with the control or actuation of driving, braking and/or additional devices at predeter mined positions of displacement of the stitch-forming elements or on other sewing machine parts.

In the operation of the control mechanism according to the present invention sets of contact springs are influenced by an actuating lever which, by means of a holding device, is directly connected mechanically with the movable sewing machine part so as to be displaced in conjunction therewith.

Conveniently the contact spring sets may be of the kind already known for use in the electrical engineering field. As required, one or more electric circuits may be influenced one or more times by using various combinations of sets of spring contacts, such as for example, working, resting, reversing, switching sequence contacts or the like.

Where it is necessary to provide a particularly reliable and exact contact device the invention includes spherical or spherical-like bodies of metal as the contact elements engaged by the actuating lever, these being arranged in cylindrical sleeves of insulating material. The end faces of these sleeves conveniently may be of metal and may have a central bore which is sufficiently large to enable the spheres to project out of the sleeves to an extent equivalent to slightly less than half their bulk.

The spheres are retained in position by helical springs located axially of and Within the sleeve of insulating material, said springs being used simultaneously as electric conductors between the spheres and the metallic ends of the sleeves where connection is made to the leads for the electric current of the control circuit.

Several control devices may be so mounted on difierent parts of the sewing machine which are positively moved independently of one another so that operation of the circuits is eflected only in a definite relative position of such parts.

The invention is more particularly described with reference to the accompanying drawings which illustrate embodiments of the invention by way of example and in which:

Figure l is an elevation showing one form of control device and is mounting beneath the work table of a sewing machine.

Figure 2 is a detail of a modification having spherical contact elements.

In the embodiment of the device illustrated in Figure l, a holder 2 is screwed to a foot 1 of the upper portion of a sewing machine, and has mounted on it a pair of contact sets by means of fixing screws 3 and 4.

These contact sets respectively consist of short leaf springs 6 and 7, relatively long leaf springs 8, 9, intermediate insulators 5, contact members Ill, 11 of insulating dune 17, 19555 material and backing members i? An actuating lever 14 is secured by means of a screw l5 to a clamping ring or annulus 16 surrounding a lifting shaft 17 for the feeder of the sewing mach 'ie.

The operation of the device is as follows:

As the lifting shaft 17 of the feeder moves backwards and forwards during the operation of stitch-forming, the actuating lever l4 abuts alternately against the contact members it? and i1 and thus alternately opens the contacts between the leaf spring.- 6 and S and the leaf springs 7 and 9 respectively.

Since the contact sets are not directly influenced by rotating parts of the sewing machine, but by such parts through the intermediary of the actuating lever having an oscillating movement, every possible temporal relationship of the electrical switching operations with the movement operations of the sewing machine parts may be achieved by simple adjustment of the springs of each contact sets.

A control utilizing the device illustrated in Figure 2 includes a pair of spherical contact elements. In this embodiment helical springs 22, which are adapted to retain spheres 23 on their seats 24 comprising metallic annular elements, to provide the required electric contact, with an actuating lever or other member 20, are adapted to slide in cylindrical sleeves 21 which are of insulating material and have metallic ends 25 remote from the seats 2d. The ends 25 function not only as mechanical abutments for the springs 22 but also in conducting electric current in the actuating circuit embodying the control device. Upon movements of the actuating member 213 which is positively effected in timed relationship with the operations of the sewing machine part to be controlled, either one or other of the spheres 23 is forced by the member 20 out of its seating position, against the resilient load constituted by its spring 22. in the result the existing electric circuit, including the lead 19, a metallic ring 24-, a sphere 23, a spring 22, a metallic end cover or wall 25 and a lead 18, for said part is interrupted.

Although the drawings show an actuating member 14, 20, in the form of a lever, it will be appreciated that this may be constituted by a cam or other device. Thus the form of the control device as illustrated is merely an example of what may be utilized, that is to say other structural forms may be adopted without departing from the invention as also may other switch combinations to meet particular requirements.

Iaving thus described the invention, what I claim as new and desire to be secured by Letters Patent, is as follows:

A mechanism, for use in connection with a sewing machine having an oscillating element and a movable device in driving connection with said oscillating element, said mechanism comprising in combinaton, an actuator secured to said element and oscillating therewith about an axis and having an end portion describing an are about said axis, two sets of electric contacts normally closed including contact members oppositely disposed about said actuator portion and projecting into said arc, said actuator being operable to engage in each direction of oscillation with its end portion a member to open the contact thereof, each contact set comprising a housing, said member including a plate having an aperture defining a seat and a spring pressed metallic sphere fitting on said seat to close an electric circuit and projecting for a short distance through said aperture into the path of said actuator portion and engageable thereby to be removed from its seat to interrupt said circuit.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Savard Sept. 18, 1923 Bryant et a1 May 21, 1940 5 Collins July 6, 1943 4- Norman Apr. 10, 1951 Campbell Aug. 4, 1953 Sargrove et a1 Apr. 5, 1955 Barber Dec. 13, 1955 

